The "Big Two" dimensions of personality (Extraversion and Neuroticism) have been interpreted as biologically based affect dispositions (Positive and Negative Emotionality, respectively). Gray's (1990) theory accounts for these dispositions by posting 2 underlying brain systems (BAS and BIS) that are sensitive to cues of reward and punishment, respectively. Predictions from Gray's theory are receiving support in studies of CNS asymmetries, studies of learning to reward and punishment, and studies of responsivity positive and negative laboratory mood inductions. However, while Gray's theory directly implicates attentional deployment (to cues of reward and cues of punishment), little research has focused specifically on individual differences in attention to affect-relevant information. The Stroop task provides a precise and well-documented tool for studying attentional processes. Moreover, an emotional version exists, and several theoretically guided improvements are proposed. Emotional Stroop tasks are ideally suited to test predictions from Gray's theory about individual differences in attentional deployment to hedonic stimuli. Ten proposed studies will address 6 broad gaps in our knowledge of personality functioning: 1) to test modified versions of the emotion Stroop task, 2) to develop and test the incremental validity of a new picture/word emotion Stroop task, 3) to use the emotion Stroop tasks to examine attentional differences associated with the constructs of Gray's theory, 4) to examine attentional deployment to both positive and negative stimulus categories, 5) to assess the relative contribution of personality traits and emotion states in producing emotional Stroop interference, and 6) to examine whether attentional interference is specific (e.g., to anger, sadness, anxiety, and disgust) or, as predicted from Gray's theory, is general to hedonic stimuli. The significance of the proposed research lies in its direct test of an important but neglected part of Gray's theory of personality, its inclusion of "positive" traits (extraversion) and positive stimuli, and the introduction of a new and modified form of the emotional Stroop task that may prove more sensitive to hedonic attentional bias. Results will advance our theoretical understanding of 2 robust and central personality characteristics and will extend the set of methodological tools useful for understanding and investigating individual differences in emotion and attention.